The Sensitivity and Specificity of Serum Phospholipase A2 Receptor Antibodies in Diagnosing Primary Membranous Nephropathy in Patients with Adult Nephrotic Syndrome and its Correlation with Serum Phospholipase A2 Receptor Staining in Kidney Biopsies.

Membranous nephropathy (MN) is one of the most common causes of nephrotic syndrome (NS) in nondiabetic adults, with about 70%-80% of cases of MN being primary MN (pMN). Many studies have shown that serum phospholipase A2 receptor (PLA2R) antibodies are a diagnostic and prognostic biomarker for pMN, with a pooled diagnostic sensitivity and specificity of 54%-82% and 89%-100%, respectively, resulting in PLA2R staining and serum PLA2R antibodies being incorporated in the management algorithms of MN. We studied the sensitivity and specificity of serum PLA2R antibodies for diagnosing pMN and its correlation with PLA2R staining in kidney biopsies in a prospective observational study of 58 adult NS subjects undergoing a kidney biopsy. Serum PLA2R antibodies were determined by indirect immunofluorescence (IF) before the biopsy. Kidney biopsies were sent for light microscopy and IF examinations. Biopsy samples with MN histology were stained for PLA2R antigens. Out of the 58 adult NS subjects, 28 were diagnosed with pMN and one with secondary MN. Serum PLA2R antibodies were positive in 12 subjects with pMN, and one had focal segmental glomerulosclerosis not otherwise specified, giving a sensitivity of 42.8% and specificity of 96.7% for diagnosing pMN. There was a significant association between glomerular staining for PLA2R (24 of 28 subjects) and a diagnosis of pMN by kidney biopsy, with a sensitivity of 82.8%. Cohen's kappa agreement between glomerular staining for PLA2R and a diagnosis of MN was 0.83 (0.57-1.08).

Type III collagen disorders: A case report and review of literature.

Collagen type III is a normal component of interstitium and blood vessels. Collagenofibrotic glomerulopathy (CG) and nail patella syndrome (NPS) are the diseases of abnormal type III collagen deposition. In spite of these curved frayed structures with a periodicity of 45-60 nm are deposited in subendothelium and mesangium in CG, they are found only in the basement membrane in NPS. The clinical features of CG are confined to the kidney, NPS has associated extra-renal manifestations. Electron microscopy is essential to make the renal diagnosis in both these rare diseases. Both the entities considered to be systemic diseases evidence to suggest similar deposition in other organs, understanding etiopathogenesis and disease progression await research.

Crystalloid glomerulopathy in monoclonal gammopathy of renal significance (MGRS).

We report a case of monoclonal gammopathy of renal significance in a 63-year-old man who presented with nephrotic-range proteinuria and renal insufficiency. The kidney biopsy showed a membranoproliferative glomerulonephritis pattern with extensive crystalloid deposits in the glomerular capillary endothelial cells and very few in the tubular epithelial cells. The immunoperoxidase staining showed kappa light chain restriction. Subsequently, the bone marrow showed 6% plasma cells which confirmed the diagnosis of monoclonal gammopathy of renal significance. He responded well to bortezomib treatment with resolution of the nephrotic syndrome and normalization of renal function after 7 months.

POEMS syndrome with renal plasmacytoma and classic polyarteritis nodosa: a case report.

POEMS syndrome is a rare conglomeration of disorders associated with plasma cell dyscrasia. The acronym POEMS is derived from main features of the syndrome namely 'polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin lesions'. Other clinical features include presence of sclerotic bone lesions, Castleman's disease, papilledema, pleural effusion, edema, ascites, erythrocytosis and thrombocytosis. Myeloma is the most common plasma cell dyscrasia associated with POEMS syndrome. Renal involvement is rare and renal biopsy is characterized by glomerular involvement with membranoproliferative glomerulonephritis and endothelial injury. We report a case of a 67-year-old male who presented with clinical features satisfying the diagnostic criteria of POEMS syndrome and had rapidly progressive renal failure. Renal biopsy showed extensive interstitial infiltration by plasma cells and concomitant presence of classic polyarteritis nodosa. Although association with small-vessel vasculitis has been reported in patients with POEMS syndrome, to the best of our knowledge, this is the first report of POEMS syndrome associated with medium-sized vessel vasculitis.